The spacewalk began at 9:11 a.m., and was the 46th devoted to assembly and maintenance of the station. Making quick work of their first task, to remove a bolt preventing activation of a cable cutter on the mobile transporter, Wolf and Sellers moved on to connect ammonia lines and remove structural support clamps that held the truss in place during launch. With Sellers and Wolf working well ahead of schedule, an additional "get ahead" task – installing Spool Positioning Devices on a pump motor assembly – was added to the spacewalk. The pump motor assembly helps to circulate ammonia through the station's cooling system. Throughout today's spacewalk the station's robotic arm, which was used as a work platform by Sellers and Wolf, was operated by NASA's ISS science officer Peggy Whitson and Mission Specialist Sandy Magnus.
Earlier in the day at 6:20 a.m. Commander Jeff Ashby and Pilot Pam Melroy pulsed Atlantis' thrusters for 35 minutes gently raising the altitude of the station by 2.3 miles. The combined results of two reboost maneuvers by Atlantis increased the station's altitude by a total of six miles, setting the stage for the arrival of a replacement Soyuz spacecraft, set for launch on October 28.
Atlantis' crew is scheduled to awaken at 3:46 a.m. Tuesday with the station crew awakening about one-half hour later. Tuesday will see some scheduled off-duty time for the two crews, allowing them some final hours together before Wednesday's scheduled undocking and departure of Atlantis from the station.